Some 1,197 flight cancellations were reported across the United States as of 8 p.m. ET, according to the flight tracking site Flightstats.com, more than the average of 657 flights canceled daily over the past 30 days. Still, it's far fewer than the 4,000 flights canceled in the storms Sunday.

Dallas/Fort Worth International Airport, which was hit by storms in the last few days, led with more than 100 departing flights canceled.

The pre-winter wintry weather isn't over. Temperatures in storm-stricken parts of the country are expected to stay about 10 to 20 degrees below normal for the rest of the week, the National Weather Service said.

Federal offices in Washington were closed Tuesday as more sleet, snow and freezing rain were expected. And a swath of 2 to 6 inches of snow was expected to fall Tuesday from Virginia to the New England coast, forecasters said.

Philadelphia can expect to get 3 to 5 inches of snow on Tuesday; New York, a little less than that.

The storm will finally leave the East Coast late Tuesday, but the mercury won't rise above freezing until at least Friday, the National Weather Service said.

Portland, Oregon, and Chicago will see snow and freezing rain this week.

The flight delays reached more than four hours at New York's LaGuardia airport and in Philadelphia, with the Federal Aviation Administration reporting Newark airport experienced delays averaging five hours and 29 minutes.

US Airways, which operates a hub in Philadelphia, had a "slow go of it," but continued to fly "where we can do so safety" according to spokesman Todd Lehmacher. The airline canceled more than 300 flights for Tuesday systemwide, the vast majority for the weather. Twelve flights headed to Philadelphia landed at other airports due to the snow.

On Tuesday, Delta Air Lines and Delta Connection reported 90 cancellations due to weather and subsequent air traffic control delays across the Northeast.

United Airlines canceled 350 flights Tuesday, out of the 4,700 scheduled, most were to and from the New York and Washington areas. "If customers are traveling today they can expect some delays and cancellations," United spokesman Charlie Hobart told CNN.

Southwest Airlines saw 82 cancellations Tuesday. Southwest spokeswoman Michelle Agnew said the airline's operation in Baltimore was hard hit, but they are recovering from the morning delays.

The major airlines all urged passengers to check their websites for the latest information.

Delta, US Airways and many other carriers have relaxed fees for passengers traveling to the impacted cities who want to change their tickets. The rules for each airline are different and can usually be found on the airline's homepage.